Final answer:
The correct answer is option b. 20.7 miles, which is the total distance run by the marathon runner when calculated using the proper number of significant figures.
Step-by-step explanation:
The correct answer is option b. 20.7 miles. When we add the distances run by the marathon runner in each part of the race, we have to make sure we are using the proper number of significant figures. The runner ran 9.5 miles in one direction, 8.89 miles in another direction, and 2.333 miles in a third direction. To find the total distance, we simply add these numbers:
- 9.5 miles
- + 8.89 miles
- + 2.333 miles
Now, we perform the addition:
9.5 + 8.89 + 2.333 = 20.723 miles
Since the fewest number of decimal places in any of the numbers being added is 1 (in 9.5 miles), we round our answer to 1 decimal place, which gives us 20.7 miles as the correct answer.